1. Field of the Invention
The present invention relates generally to an apparatus and method for providing information on a packet data gateway (PDG), and in particular, to an apparatus and method for providing information on a PDG to a terminal and allowing the terminal to connect with the PDG easily.
2. Description of the Related Art
A packet data gateway (PDG) is a node of a network serving as a gateway used for connecting a terminal in an IP multimedia subsystem (IMS) in a 3rd Generation Partnership Project (3GPP) system. For this purpose, packet exchange and control information exchange for the packet exchange between the IMS and the 3GPP system are performed through the PDG.
FIG. 1 is a diagram illustrating a general procedure of IMS registration.
Referring to FIG. 1, user equipment (UE) 110 connects with an access network such as wireless LAN (WLAN) in steps 1, 2 and 3. Thereafter, the UE 110 retrieves an address of a PDG 122 in step 4 and establishes a tunnel to the PDG 122 in step 5. In steps 6, 7 and 8, the UE 110 connects with core networks 150, 160, 165 and 170 to perform an authentication process.
When the UE 110 does not know the address of the PDG 122, the UE 110 can obtain the address by retrieving a domain name system (DNS) 120. As described above, the UE 110 must connect with the PDG for the IMS registration. However, current standard specifications do not describe processes of notifying and storing information on the PDG (hereinafter PDG information).
FIG. 2 is a diagram illustrating general configuration of networks using PDGs.
Referring to FIG. 2, generally, UE 250 has information on a home network 210 including information on a PDG 215 of the home network 210, so that the UE 250 can connect with the home network 210 without difficulty in step A.
However, when the UE 250 attempts to connect with a visited network 230 in step B, the UE 250 must know an address of a PDG 235 of the visited network 230.
As described above, prior standard specifications do not describe PDG information and provide an update of the PDG information and thus there is a need to define the processes of storing and updating the PDG information.